In recent, years, the reduction in size and thickness of mobile telephones has been promoted. With this, antennas have been reduced in size, and a distance between a mobile telephone and the human body, particularly head, during a call has been reduced more.
The size reduction of antennas causes the decrease of the gain thereof. Also, the reduction of the distance between the mobile telephone and the human body during a call increases the Specific Absorption Rate (SAR) of electric waves in the human body. Therefore, in order to further promote the reduction in size and thickness of mobile telephones, it is necessary to improve the gain of the antennas and reduce the SAR.
According to the art disclosed in the Patent Document 1 aiming to solve the above problem, a passive element is provided in the vicinity of an antenna element, and substantially parallel to a width direction of a ground plane so as to be adjacent to the ground plane. When the passive element is located on a side closer to the human body relative to the ground plane during a call, the gain during the call is improved by causing the passive element to have a length so as to operate as a director. When the passive element is located on a side opposite to the human body relative to the ground plane during a call, the SAR is reduced by causing the passive element to have a length so as to operate as a reflector.    Patent Document 1: Japanese Laid-Open Patent Application Publication No. 2003-258523